An intermolecular Ti(IV)-mediated cyclopropanation reaction has been used to
synthesize substituted 2-phenylcyclopropylamines and constrained analogues of
the neurotransmitters histamine and tryptamine. Many potent inhibitors of
monoamine oxidase were made in 1 to 5 steps from readily available starting
materials and have been shown to mimic hallucinogens.